Control apparatus



JN. H. KLREVER Dec. i5, 3949 CONTROL APPARATUS 4 She'tS-Sheet l Filed May 3l, 1945 W. H. KLIEVER CONTROL APPARATUS Dec. 6, .1949

4 Sheets-Sheet P,

Filed May 51, .1945

Ctorneg Dec. 6, 1949 w. H. KLIEVER l I 2,490,735

CONTROL APPARATUS Filed'may 31, 1945 4 sheets-sheet 3 l' I l l 'Ilm Enventor khan@ f. //EVEP Gttorneg Dec. 6, 1949 w. H. KLM-:VER

CONTROL APPARATUS 4 Sheets-Sheet Filed May 3l, 1945 Patented Dec. 6, 1,949

2,490,735 CONTROL APPARATUS Waldo H. Kliever, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Appueation May 31, 1943, serial No'. 489,175

I ol. 33-222 l 16 Claims.

This invention relates to control apparatus and more particularly to devices in which the position of a continuously rotatable member is made effective at a distance to actuate an indicator or to Operate any device which it is desired to make responsive to the angular position Of the rotatable member. Since the invention is particularly adapted for use as a remotely indicating means with a magnetic compass, my preferred embodiment of the invention discloses it in association with such a compass, but it will be readily understood that the invention is adapted to be associated with any rotating member which it may be desired to use as a controller.

Devices for broadly making effective at a distance changes in the position for example of a compass needle are known, but these devices are subject to various difficulties as will hereinafter be pointed out. A particular disability from which previous compass devices have suffered lies in the fact that they have all required mechanical means near the compass needle itself, such for instance as an electric motor, for restoring the relationship between the compass needle and the indicator or actuator after unbalance due to movement of the needle has thrown the mechanism into operation. It is a further object of this invention to overcome this disability in prior art devices.

An object of this invention is to provide a new and improved remotely indicating or controlling apparatus.

A further object of this invention is to provide an improved remotely indicating or Operating compass.

Another object of this invention is to provide an improved electrical system for continuously transmitting the angular position of a continuously rotatable member, without placing an'y appreciable load on the rotatable member.

Still another object of this invention is to provide an improved remotely indicating or operating compass which is continuously responsive to the angular position of the controlling compass member.

A still further object of this invention is to provide an improved electrostatic device having a plurality of xed members and having further rotatable means adapted to cooperate with the xed members to form a number of electrical condensers.

Still another object of my invention is t provide a device for torque amplication, wherebya minute signal torque produces an enormously larger response torque acting through an angle 2 having any desired relation to the angle through which the signal torque acts.

Other objects and advantages of the present invention will become apparent from a study of the specification, claims, and appended drawings, wherein:

Figure 1 is a diagrammatic showing of an electrical circuit including a rst embodiment of my invention shown in more detail in Figures 6 and Figure 2 is a longitudinal sectional view of a second embodiment of a portion of my invention, the section being taken along the line 2 2 of Figure 3;

Figure 3 is a transverse sectional view of the same device, the section being taken in a plane indicated by the line 3 3 of Figure 2;

Figure 4 is a fragmentary view similar to Figure 2 but showing a modication of the second embodiment of my invention;

Figure 5 is a transverse sectional view similar to Figure 3, but taken along the line 5 5 of Figure 4;

Figure 6 is a diagrammatic showing of the rst embodiment of the invention not taking full advantage of al1 the potentialities of my invention and yet having al number of features of convenience;

Figure 7 is va'longitudinal sectional view of the embodiment of my invention shown in Figure 6, the section being taken along the line 'I 'I in Figure 6; and

Figure 8 isa diagrammatic showing similar to Figure l, but including the embodiment of my invention shown in detail in Figures 2, 3, 4, and 5, and showing Athe system in an electrically unbalanced state.

Referring now to Figure 1 in which my complete invention is most clearly illustrated, it will be seen that the invention is made up of four principal parts of which numeral IIJ refers to an electrostatic pickup device, numeral I I to an amplifier and motor control unit, numeral I2 to a motor, and numeral I4 to a potential dividing device. An embodiment of the pickup and potential divider of this system is disclosed in Figures 6 and 7.

The electrostatic device IIJ comprises a set of plates I5, I6, I'I and I8 which are shown as spaced portions of a cylinder. These plates are provided with electrical connections 20, 23, 22, and 2l respectively, for purposes to be disclosed presently. Concentric with the plates above mentioned, are shown another pair of plates 24 and 25 electrically insulated and supported by a member 26 in such fashion as to pivot around the axis 21 of the cylinder. Plates 24 and 25 are provided with conductors 28 and 29, respectively, which are connected to the input terminals of the amplifier and motor control unit I I as shown in the figure. Member 26 also carries a magnetic needle 3D for responding to the horizontal component of the earths magnetic field. The plates I5, I6, I1, I8, 24, and l25 cooperate toform 'a plurality of condensers connected in a capacitance network.

Turning now to the potential dividing device I4, it will be seen that this device maybecomposed of a toric coil 39 of resistancewire comprising four sections or resistors 3I',"'3'2, 3 3Lan'd 34, corresponding generally withthe-plates I5, I6, I1 and I8 of the electrostatic member I0 1and connected together sequentially end Lto v en'drelation to comprise a single closed electric circuit. A pair of contactor elements 36 and 31 are arranged for rotation about an axis 35 in such fashion that they are continually in conductive contact `with the toric coil I4. Spaced around the coilwill be seen connector elements 38,'48,"4I and 42'to` which are connected conductors 2l, 22, '23"and 20,' respectively. Resistors 3l, 32, 33, and 34 and 'contact elements 36 and 31 cooperate to comprise'a resistance network. Contactar elementsv 36 and 31 are connected as by conductors' 43` and 45 with a source of alternating current,`which may be the secondary winding of a transformer II I.

From a consideration ofthe drawi`ng,`it will be'seen that the potentials with'respect to ground upon the various plates I`5,'I6, I1, 'and lI8 of the electrostatic device will be determined 'by Vthe position of the contactor elements 36 and '31 on the resistance coil 39. Thus, supposingthe instantaneous polarity of the alternating'current to be as shown, conductor "43 'being positive "and conductor "45 being negative,.it `vlillbe seen" that plate I6 is most positivly'chrgedfand'tl'iat. plate I8 is most negatively charged while Athe'charges of plates I and I1 areatsome intermediate values. It will be seen that the angular vdimensions of the fixed plates of'the Vels'a'ctrosta'tic device and of the coil portions comprising the torio c'oil may be related, sotli'at rotation of the respective rotatable portions ofthe'se two devices through equal angles brings aboutequal and opposite changes in the voltageV across conductors 28 and 29. Accordingly, in the position as shown in the figure the potentials'on plates 'I5'and'l1 are equal and no signal will be impressedon the input of the amplifier. As will be more fully pointed out below, for any positionf'of vmember 26 there is a position of contacts`36`an`d'31 suchthat no signal is transmitted to the amplifier. I will refer to any such simultaneous arrangement of the movable members asa balance`or zero position of the system.

Let the plates 24 and 25 have'been rotated in a counter-clockwise direction by the action .of the compass needle or some other controlling member, the instantaneous potentials with respect to ground on plates I5, I6,y I1 and lI8 again being those illustrated. The potential induced upon plate 24 is no longer simply that due to plate I1, but now includes a component due to positively charged plate I6, and the .potential induced upon plate 25 includes acomponent due to negatively charged plate I8. Thus if the instantaneous potential difference Vbetween contactors 36 and 31 is 12 volts, of they indicated polarity, and if the angle through which .plates 24 .and 25 have been rotated is 45, a positive potential of 3 volts will be induced on plate 25 and a negative potential of 3 volts will be induced on plate 24, both potentials being measured from the center tap IID of the transformer. As the cycle continues, the potentials on conductors 43 and 45 vary, as do those on plates l5 and I8, and hence the induced potentials on plates 24 and 25. However, it will be observed for any given angular setting of the .rotatable plates, that they attain their maximum potentials at the same instant in the cycle as do the fixed plates.

`Now let the plates 24 and 25 have been rotated in a clockwise direction, the instantaneous potentials on plates i 5, I6, I1, and i8 still being those illustrated. The potential induced upon plate 25 now includes a component due to negatively charged plate I8, and the potential induced upon plate 25 includes a component due to positively charged plate I5. Thus if the instantaneous potential difference between contactors 36 and 31 is l2 volts, of the indicated polarity, and if the angle through which plates 24 and 25 have been rotated is 45, a negative potential of 3 'volts will be induced on plate 25 and a positive potential vof 3 volts will be induced on plate 24, both potentials again being measured from the center'tap IID of the transformer. As the cycle continues, the potentials on conductors 43 and 45 vary, as do those on plates I6 and I8 and hence the induced potentials on plates 24 and 25. It will again be observed that for any given angular turning of the rotatable plate they attain their maximum potentials, although this time of the opposite polarity, at the same instant in the cycle as before.

It will now be obvious that movement of plates 24 and 25 out of the balanced position causes potentials to be induced on the plates, theY magnitude increasing with the size of the angle, and the polarity depending upon the direction of rotation. A reversal of polarity in alternating current circuits is a phase shift of 180. Therefore, we may have impressed on the input of the amplifier either no signal or a signal of variable intensity which may be either in phase with or 180 out'of phase with the'inducing potential.

The amplifier and motor control unit to which I have previously referred may be of any suitable type. The construction and operation of one such amplifier are clearly set forth for example, inthe copending application of Albert P. Upton, Serial No. 437,561, led April 3, 1942, Pat. No. 2,423,534 and assigned to the assignee of the present application. For the sake of clarity I have illustrated the most simpliiied form of a conventional amplifier and motor control circuit suchas is vwell known to those skilled inthe art. Thus it will be apparent that one winding of the field of motor I2 is continuously energized through a capacitor from the source of alternating current, while the other field windingV is energized from the output of electrostaticdevice I0, amplified in a conventional fashionin the triode tube. As previously pointed out, the output of device I0 is either in phase with thesource or 180 degrees out of phase with it, andhence the current in the amplifier energized winding of the motor eld leads or lags the current in the line energized winding by degrees. Forward or reverse operation of the motor then occurs as the former current lags or leads the latter. In the absence of signal current, no operation of motor I2 takes place.

The shaft 55 of motor I2 carries an operating member 49, which may be an indicator or a controlling member associated for example with a rudder bar or a gyroscope.

I will now describe the operation of my invention. It will be understood that in setting up the invention the control device, an indicator needle located on a dial graduated in the points of a compass for illustration, has been adjusted to a predetermined position when the controlling element 26 is in a desired position with respect to iixed plates I5 to I8, and no potential difference exists between conductors 28 and 29.

If now for any reason element 26 rotates in either direction around its axis, plates 24 and 25 receive induced charges of a polarity and magnitude dependent on the size and extent of the angle of rotation, and the induced charges acting through the amplier and motor control unit operate the motor accordingly in forward or reverse direction at a greater or lesser speed. The action of the motor has been so arranged that on the signal due to the disturbance of the balance in either direction the motor operates to move contactors 36 and 3l so as to compensate for the change in position of the plate by a suitable change in the impressed voltages. ing plate moves in a counterclockwise direction, the contactors are rotated to decrease the positive potential on plate IB and the negative potential on plate I8, and to create a negative potential on plate I1 and a positive potential on plate I5. This motion continues until the charge inducing potentials on the xed plates are such, considered with the relative areas of plates 25 and 29, respectively, opposing each iixed plate, that the resulting induced potentials on plates 24 and 25 are equal. When this condition is reached, no potentials are impressed on the input of the amplifier and operation of the motor is then interrupted. If suitable gear ratios and graduation values have been selected, the indicator 49 is now again in agreement with the position of element 26. From a consideration of the above statement, it will be obvious that I have devised an electrostatic means for continuously transmitting the position of a continuously rotatable member.

Referring now to Figure 2, there will be found a preferred embodiment I of the electrostatic device of my invention as specically applied to the art of remote indicating compasses. A representation of a system analogous to that of Figure 1 but slightly adapted for use with the preferred form of my invention is found in Figure 8. In Figure 2 a magnetic needle 159 is unitarily mounted on a shaft I for rotation therewith in upper and lower bearings 52 and 53, respectively, carried respectively by upper and lower adjusting screws 54 and 56. Needle Sii is contained in a recess 5'I in a magnetically transparent cap member 58. The cap member is fastened to a housing 59 by rods 60 sweated into the cap as at 6I, passing through aligning holes 62 and further holes 53 in the housing, and fastened by nuts 34 threadedly engaging threaded portions 65 of the rods. The shaft 5I and the rods 60 have the same thermal coefcient of linear expansion, in order that changes in ambient temperature may not cause the shaft 5I either to become loose or to bind in its bearings, and it will be observed that spaces 6l are provided to allow for the relative movement of rods 99 and housing 59.

A electrically conducting disk 69 is held in position above the magnetic needle 5I) by a snap ring 19, whereby to electrostatically shield the If the rotatneedle from portions of the device above the disk.

Separated from the housing 59 by an insulating layer 'I2 are a plurality of brass blocks 14, l5, 'I6 and 'II in the form of sectors of an annulus of U-shaped cross-section. Insulating members 'I3 are provided to separate the blocks from one another, and the blocks are provided with shallow holes I8 adapted to receive the pins 'I9 of Bakelite insulating elements 89. The ends of these elements are cut off at an angle whereby they may cooperate with set screws 8l mounted in angularly tapped holes 83 in cap member 58, to hold the brass sections firmly in place.

Unitarily mounted on the shaft 5I for rotation therewith is a thin vane 84 of electrically conducting material in the form of a circular sector whose center coincides with the axis of rotation of shaft 5I. This vane moves in a circular recess formed in the brass blocks by cutting therein grooves 86. Thus the vane and the brass blocks may cooperate, depending` upon the relative positions of the vane and the blocks, to form a number of electrical condensers. A counterweight 83 is provided to balance the moment couple of the vane 84 at the ends of the shaft. The brass blocks are provided with connecting screws 89, 99, 9i, and 92 whereby electrical connections may be made with them.

Spacedly surrounding shaft 5I above the insulating member 'l2 is an electrically conducting sleeve supported between insulating collars 96 and 91 by an aluminum disk 98 held in place by a snap ring 99. Sleeve 95 and shaft 5I comprise the two conductors of a coaxial condenser and the air in the space between them comprises the dielectric of the condenser. Electrical connection is made between amplier II and the coaxial condenser by means of conductor 2S', which terminates at a conecting screw 92 in sleeve 95. The coaxial condenser is thus connected in series between the electrostatic pickup device and the amplifier, and conducts the alternating current signal output of the pickup, presenting thereto an impedance determine/i by its dimensions just as would any conventinally constructed condenser.

The modification of the device as disclosed in Figure 4 differs from that in Figure 2 only in the fact that counterweight 88 has been replaced by a mica vane counterweight |96, in diametrically opposed relation to vane 84 and travelling in the same circular recess in the brass blocks.

In the embodiments of the invention shown in Figures 2 and 3 it is obvious that a single rotatable plate has been used instead of a pair of rotatable plates shown in Figure 1, and I conceive the spirit of my invention to be broad enough to include this modication. This is illustrated in Figure 8, where I have redrawn Figure l to substitute for conductor 29 and plate 25 a connection 29 which grounds one pole of the input of the amplier, and to show the provision of a grounded center tap I IIJ in the secondary winding of the transformer III providing current to potential divider I4.

The operation of this device, in a system as illustrated in Figure 8, does not diiier materially from that which I have previously described. It will at once be apparent that the potentials on the various brass blocks diier from the ground potential as the position of contactors 35 and 3l varies. The single vane receives induced potentials with respect to the ground proportional to the relative areas thereof opposed to the blocks, and to the potentials on the blocks, in a manner similar to that already describediwithreference.

to Figure l. The alternating induced voltage is transmitted through the coaxial condenser` and energizes amplifier Iltolactuate motorv I2; This results, under conditions asshown in Figure 8, in rotation of contactors 36 and `'lin a counterclockwise direction through approximately 45 degrees, when the potentials in plates land il acquire such magnitudes that-no voltage is induced between plate 8f3 and ground, andmotor operation is interrupted.

In Figure 6, I have illustrated a modiiication of my invention combining the electrostatic Vdevice and the potential divider device in one instrument, and embodying the system illustrated in Figure 1. I consider this modication less preferred since it fails to take advantage of the full potentialities of my invention, but itnevertheless has certain advantages oi compactness and convenience, particularly where the device is controlled by some device other than a magnetic compass. In Figure 6, a disk 26 is arranged for rotation with the shaft or otherfobject whose angular position is to be indicated or otherwise utilized. Unitarily attached to this disk as by rivets IES are a pair of plates 24 and 25 in the form of portionsv of a cylinder. Fastened in a similar fashion to a fixed disk I3I of insulating material are four other plates I8, I5, I6, and Il shaped to comprise portions of a cylinder slightly larger in radius than that of plates 2d and 25. A pair of slip rings |98 and |99 may be carried by disc Ii for engagement by suitable sliders connected to plates 2e and 25': one of these sliders appears in Figure 7. Conductors 23 and 29 are connected to slip rings ISS'and |98 for making electrical connection with plates 24 and 25, all respectively, and amplier I I.

Also mounted in any convenient fashion on the member itl is an endless coil 39 of resistance wire in the form of a torus. This coil is divided circumferentially into four portions32, 33, 35, and Si. The points of junction of these portions of coil E36 are connected by conductors, 22, ZI,

and 23 with the iixed plates previously mentioned. An annular ring I56 also ofr electrically insulating material, is rotatable aboutl the toric coil and carries contacting elements 3l and 36 which continually make electrical contact with the coil. These contactingelements are designed -to be connected to a source offalternating current and communicate this current'to the coil. The outer edge of annulus I56 maybe graduated as shown and an index ISI may be located on some portion of the frame of the device. Any TVitional mechanical means may be provided for causing 56 to rotate with respect to ISI and It. For the sake of illustrationA only, I have shown element I as being provided -with a series of gear teeth I with which is adapted to engage a gear Ito be driven by shaft 55. This is no more than a mechanical equivalent of the direct connection shown in Figure 1between shaft 55 of motor I2'andcontactors 36 l'and 3l', which in that ligure are the equivalentof contactors 3l and 35 in Figure.

The operation of this embodiment of the device is that set forth with reference to Figure l.

eviation of the compass needle from its zero position causes dierential interleaving of the conducting plates in the fixed plates, impressing a potential on the ampliiier which may lead or lag the primarypotentiaLland accordingly the motor runs in oneldirection orathe other, altering the potential upon .the xedplates Luntil `this sig-V 8i nal disappearsffromthe:-amplier Graduatonsl Het rotate past index ISI atthe sametiinethatA contacts 3l and 35 rotate about the coil, so that upon cessation of signal the indication of l index it is the Asame as the actual position of the/frotary member.

I have explained the operation of my invention in the terminology of electrostatics. An alternative explanation in electro-dynamic terminologyfollows, reference first-being had to Figure l: the structure of my invention is the Same, of course, whichever explanation is preferred.

A number of paths can be followed by the alternating current supplied by transformer III- from conductor 3 to conductor 45: of these paths, only two are of significance as affectingA the operation of motor I2. 'I'he first significant path can be traced as follows: conductor 43, contactor 3S, connection 4I, conductor 23, plates I6'l and l, conductor 2l, connection 38, contactor 3l, and conductor 55. The second signiiicantr path can be traced as follows: conductor 43, contactor resistance section 33, connection 130,

conductor 22, plates Il and I5, conductor 25, conf nection resistance section 3l, contactor 31,

and conductor irl-5.

In the positions of the potential divider and pickup member shown in Figure l connec tions and are at the same potential, andthereiore no current flows in the second circuit just traced. Slight current may flow in the rst circuit: however, due to the arrangement of member 25, no potential difference appears between plate 2e to plate 25, and this results in a zero output to amplifier II.

If member 2t is rotated in a counter-clockwise directionthere is a predominant ow of current from plate i t through plate 24, conductor 2S, amplier conductor 29 and plate 25 to plate 26 during the indicated half cycle of the source= and in the opposite direction during the next half cycle: this results in the appearance of a signal voltage between conductors 28 and 29 'which is of a fixed phase with respect to the source, and the motor is energized to rotate in a counter-clockwise direction. The voltage between plates I6' and I8 is accordingly reduced, which reduces the signal voltage reaching the amplifier, and also an increasing potential diierence appears between plates I l and i5 oi a nature tending to cause flow of current through plate 2Q, conductor 28, amplifier l, conductor 2Q and plate I5. The effect of this current in the opposite direction through ainplier i E opposes that passing through plates and iii. Operation of motor I2 continues until the signal voltage has completely disappeared from conductors 28 and 29, when the motor stops.

Il member 2e rotates in a counter-clockwise direction, there is a predominant owof current from plate to plate 25 during the indicated half cycle of the source, and in the opposite direction during the next half cycle: this results in the appearance of a signal voltage between conductors 2t and 26 which is of a second phase with respect to the sourcethat is, of opposite phase to that resulting from counter-clockwise rotation of member 2and the motor is energized to rotate in a clockwise direction. The voltage between plates le and E8 isagain reduced, reducing the signal voltage reaching the amplier, and an increasing potential difference again appears between plates Il and I5,Y. tending to cause ilow of current through conductors 28 and 29 in theI opposite direction to .that due .toV plates I6 and 9 I8. Operation of motor I2 continues until the signal voltage has completely disappeared from conductors 28 and 28, when the motor stops.

In Figure l my electrical system is shown in its normal or balanced condition. Figure 8, on the other hand, is prepared to show the preferred embodiment of my invention in an electrically unbalanced condition. In Figure 8 there are again a number of current paths, but only four are operatively significant, and of these not more than two are signiiicant at any one time; in certain special cases only one path is signiiicant. The signiiicant paths are determined by the rotated position of vane 84 and include the block or blocks with which it is in apposition. In Figure 8 the signiiicant paths are two in number. The iirst can be traced as follows: conductor 43, contactor 35, the upper portion of winding 33, connection 40, conductor 22, a condenser comprising plate I4 and the apposed portion of Vane 84; shaft 5I, the coaxial condenser, conductor 28', the input resistor of ampliiier I I, and ground connections 23 and IIO. The second path may be traced as follows: conductor 43, contactor 38, the lower portion of winding 33, connection 4I, conductor 23, a condenser comprising plate 'I'I and the apposed portion of vane 84, shaft I, the coaxial condenser, conductor 28, the input resistor of ampliiier I I, and ground connections 29' and I I 0.

Current flows in each of the paths just traced and the voltage drop across the ampliiier input resistor is determined by the sum of the two currents. The ampliiier accordingly energizes the motor to rotate shaft 35 in a counter-clockwise direction moving contactors 38 and 3'! around resistance 39 to vary the amount of resistance in series with each of the condensers comprising portions of vane 54 and thus to change the currents iiowing through the condensers.

When the shaft 35 has rotated so that contactors 3S and 37 engage connections 4I and 38, respectively, connection 4U is at ground potential, since windings 33 and 32 are of equal resistance and ground connection I I0 is connected to the center of the transformer secondary. Plate 'Id is therefore at ground potential and no current flows through the amplifier input resistor from the circuit including plate I4. nection 4I, however, is at its maximum potential and a maximum current flows through the amplier input resistor from the circuit including plate '11.

Con- L v Further rotation of shaft in the same direction reduces the flow of current in the circuit including plate l1. Moreover, a current now iiows in the circuit including plate 'I4 of the opposite phase since connection l!! is now bevond the centmnr the resistance included between contactors 4 f- The zero or balance point of the system. at 'A which operation of motor l2 was interrupted. is therefore that at which equal and opposite currents tend to now in the amplifier input resistor from the two circuits including vane 84..

This balance position is not that at which FOY any position of vane 84 there is only one posithat the invention basically comprises a torquel amplifier. The torque exerted on the needle by the earths magnetic field, when the needle is displaced from the magnetic meridian by any practically occurring angle, is minute. Yet in one embodiment of my invention torque outputs yof the order of 300,000,000 dyne-cm. have been observed. Thus an enormous torque amplification is possible.

In the modifications of my invention I have illustrated it is apparent that the angle through which the output torque acts is equal to the angle through which the input torque acts. However, those skilled in the art will immediately perceive that provision of suitable reduction means between motor I2 and shaft 55 will make possible any desired ratio between the two angles.

While I have shown and described certain preferred embodiments of my invention, further modiiications Awill readily occur to those who are skilled in the art, and I therefore wish my invention to be limited only by the scope of the appended claims.

I claim:

1. In a control device, in combination, a iixed index, a first member of electrically insulating material, said member being continuously rotatable with respect to said index, graduations carried by said member adapted to cooperate with said index, radially disposed electrical contact elements unitarily mounted on said member for rotation therewith, a second member of electrically insulating material, said member being iixed with respect to said iirst member, a resistance coil carried by said second member, said resistance coil continuously contacting said contact elements, a plurality of circumferentially equidistant electrical connections to said resistance coil, a like plurality ofcircumferentially equidistant electrically conducting elements carried by said second member, said electrical connections leading to said elements, a third member of electrically insulating material. said third member being continuously rotatable, a pair of electrically conducting elements mounted on said third member for rotation therewith. said pair of elements cooperating with said plurality of elements to comprise electrical condensers. said elements being so arranged that each of said pair of elements may comprise a condenser with each of said plurality of elements, means continuously providing electrical connections with each of `said pair of elements. a motor, means operatively connected to said last mentioned means for reversiblv actuating said motor. means providing electrical energy to said contact elements on said iirst member, controlling means unitarily mounted on said third member and causing rotation thereof, and means connecting said motor in driving relation to said iirst mentioned members.

2. In a device of the class described, in combination: a source of electrical energy; a closed resistance network comprising a number of resistors greater than two; means variably connecting said source with said network, whereby spaced points on said network may acouire unitarily Variable potentials with respect to a selected point; an adjustable capacitance network comprising a number of capacitors greater than two and having input terminals and an output circuit; means connecting said points on said re- 11 sistance network with said .input terminals of said 'capacitance network; a movable controlling member; means 'connecting said controlling member'with said'capacitance'network for causing adjustment of said network; a motor; .and

means electrically connecting said motor, said source,` and the output circuit of said capacitance knetwork for energizing said .motor from said source in accordance with-'the adjusted .condition 0T said network corresponding to the .position of 'said controlling member.

3. In a device of the class described, in combination: a source of electrical energy; a closed resistance network comprising a .number of resistors vgreater than two; means variably connecting said source 'with said network, whereby spaced ,points on said network may .acquire unitari-ly variable potentials with respect to a seected point; an 'adjustable capacitance network comprising Ya number of capacitors greater than i two and having input `terminals and an output circuit; means connecting said points Von said resistance network with the input terminals of said capacitance network; a movable controlling member; member with said capacitance network for causing adjustment of said network; a motor; means electrically connecting said motor, said. source, and the output circuit of said capacitance network for energization `from said source in accordance with the adjusted condition of said network corresponding to. the position of said controlling member; and ,means connecting said 'motor with said variableconnectingmeans for unitarily varying said potentials of said points.

4. In a device of the class described,- in combination: a source of electrical energy; a closed resistance network comprising a `number of resistors greater than two; means variably connecting said Vsource kwith said network, whereby spaced points on said network may acquire unitarily variable potentials with respect to aselected point; an adjustable capacitance .network comprising a number of capacitors greater than two having input terminals and an output circuit; means connecting said points on said resistance network with the input 'terminals of said capacitance network; a controlling member movable in response to a condition; means connecting said controlling member with said capacitance network for causing adjustment of said network; a motor; means electrically connectingsaid motor, said source, .and .the output circuit of vsaid capacitance network for energization from .said source in accordance with the adjusted condition of said network corresponding to the position of said controlling member, means to be actuated in accordance with the value of said condition, and means connecting said last named means with said motor for actuation thereby.

5. In a device of the class described, in combination: a source of electrical energy; a resistance network; means variably connecting said source with said network, whereby spaced points on said network may acquire unitarily variable potentials with respect to a selected point; an adjustable capacitance network comprising a number of capacitors greater than two and having input terminals, and an output circuit; means connecting said points on said resistance network with the input terminals 4oi? ,said capacitance network; a movable controlling member; means connecting said controlling member with said capacitance network for causing adjustment of said network; a motor; means electrically connecting means connecting said .controlling said motor, said source, Yand the output circuit of said capacitance network for energizing said motor from said source in .accordance with the adjusted condition of said network correspondv5 ing to the Vposition of said controlling member.; said resistance network comprising a number of resistors greater than two sequentially joined in end to end relation to .form a closed electric circuit, each ,junction of two of .said resistors comprising one of. said spaced points, and spaced contact members unitarily slidable along said resistors for conducting electrical energy to said network inaccordance with .the position of said members.

.6.. 'In a device of the .class described, in combination: a source o'f electrical energy; la closed resistance networkcomprising a number .of resistorsgrea'ter than two; means variably connecting said source .with said network, Ywhereby spaced points on said network may acquire Iunitarily variable `potentials with respect to va selectedpoint; an adjustable capacitance network having input terminals .and an .output circuit.; means connecting said points on said resistance network with theinput terminals of said capacitance network; a movable controlling member; means connecting said controlling member with saidcapacitance .network for causing adjustment of said network; a motor; meanselectrically connect'ing said motor, said source, and the. output circuit .of .said capacitance network `for energizing said motor from said source inaccordance with the adjusted condition of said .network corresponding to the position of said controlling member: said capacitance network comprising three or more electrically .conducting elements, an assembly including at least one further electrically conducting member, and means mounting said assembly for rotation, with respect to said plurality of elements, whereby said member may cooperate with the elements of said plurality to comprise a number of capacitors greater than two, the arrangement of said elements and said assembly being such that said member may com- 45 prise a condenser with 'any element or any two adjacent elements of said plurality.

7. In a ,device of the class described, in combination: a source of electrical energy; a resistance network comprising a number of resistors ..50 greater than two; means. variablyv connecting said source with said network, whereby spaced points on said network may acquire unitarily vvariable potentials with respect to a Vselected point; an adjustable capacitance network .having `lili input terminals and an .output circuit; means connectingr `said points on saidresistance network with the input terminals of said capacitance network; a movable controlling member; means connecting said controlling Vmember with said ca- 60 pacitance network for causing adjustment of said network; a motor; means electrically connecting said motor, ,said source, andtheoutput circuit of said capacitance network for energizing said motor from said source inaccordance .with the adjusted condition of saidnetwork corresponding to the position of said controlling member: said capacitance network comprising asetof electrically conducting Yelements carried by said controlling member for rotation therewith, a further set or three or more electrically 4conducting elements, and .means mounting a first ,of said .sets for rotation with respectto the second of said sets so that each element ,of saidrst set maybe aligned with the elements of said second set to 'Il comprise a .number of capacitors greater than two, the arrangement of said elements being such that said relative rotation may cause each element of said first set to comprise a condenser with any element or any two adjacent elements of said second set.

8. In a device of the class described, in combination: a source oi electrical energy; a resistance network; means variably connecting said source with said network, whereby spaced points on said network may acquire unitarily variable potentials with respect to a selected point; an adjustable capacitance network having input terminals and an output circuit; means connecting said points on said resistance network with the input terminals of said capacitance network; a movable controlling member; means connecting said controlling member with said capacitance network for causing adjustment of said network; a motor; means electrically connecting said motor, said source, and the output circuit of said capacitance network for energizing said motor from said source in accordance with the adjusted condition of said network corresponding to the position of said controlling member: said resistance network comprising a number of resistors greater than two sequentially joined in end to end relation to form a closed electric circuit, each junction of two of said resistors comprising one of said spaced points, and spaced contact members unitarily slidable along said resistors for conducting electrical energy to said network in accordance with the position of said members; said capacitance network comprising a plurality oi electrically conducting elements, an assembly including at least one electrically conducting member, and means mounting said assembly for rotation, with respect to said plurality of elements, whereby said member may cooperate with the elements oi said plurality to comprise a number of capacitors greater than two, the arrangement of said elements and said assembly being such that said member may comprise a condenser with any element or any two adjacent elements of said plurality.

9. A remotely indicating compass comprising,

in combination: a source ci electrical energy; an endless resistance network; means variably connecting said source with said network, whereby spaced points on said network may acquire unitarily variable potentials with respect to a selected point; an adjustable capacitance network having input and output terminals; means connecting said points on said resistance network with the input terminals of said capacitance network to comprise a telemetric system which can be balanced for any variation of connections 'oetween said source and said network established by said first named means; a magnetic needle, means mounting said needle for unlimited rotation; means mechanically connecting needle with said capacitance network for causing adjustment of said network; a motor; means connecting said motor with said source and with the output terminals of said. capacitance network for energization from said source in accordance with the adjusted condition of said network corresponding to the position of said needle; an indicator of azimuth, means connecting motor with said indicator for actuation thereof, and further means connecting said motor with said variable connecting' means for causing unitary variation of said potentials of said points simultaneous with said actuation of said indicator.

10. In a device of the class described, in combination: a plurality of resistors in the form of circular arcs connected together to comprise a closed circular resistance network; a like plurality of electrically conducting plates equally spaced about an axis; means connecting said plates, in sequence, to points of connection oi said resistors, also in sequence; a pair of contact elements; means pivotally mounting said contact elements for rotative sliding upon said circular network in diametrically opposed relation; a pair or" further conducting plates; means pivotally mounting said further plates for unrestricted rotation about said axis and for cooperation with said first named plates to comprise a capacitance network; means connected to said Contact elements for energization thereof with alternating voltage; and means connected to said further plates for responding to potential differences therebetween.

11. In a device of the class described, in combination: a plurality of resistors in the form of circular arcs connected together to comprise a closed circular resistance network; a like plurality of electrically conducting plates equally spaced around an axis; means connecting said plates, in sequence, to points of connection of said resistors, also in sequence; a pair of contact elements; means pivotally mounting said contact elements for rotative sliding upon said circular network in diametrically spaced relation; a pair of further conducting plates; means pivotally mounting said further plates for unrestricted rotation about said axis and for cooperation with said first named means to comprise a capacitance network, ymagnetic means carried by said last named means for causing the same to rotate in response to the earths magnetic eld; an indicator; means connected to said contact elements for energization thereof with alternating voltage; and means connected to said further plates for rotating said contact elements and actuating said indicator in response to potential differences between said plates.

12. In a device of the class described, in combination: a plurality of resistors in the form of circular arcs, connected together to comprise a closed circular resistance network; a like plurality of slotted blocks of electrically conducting material; means mounting said blocks about an axis with their slots inwardly directed in coplanar relationship; means connecting said blocks, in sequence, to points of connection of said resistors, also in sequence; a pair of contact elements; means pivotally mounting said contact elements for rotative sliding upon said circular network in diametrically opposed relation; a vane of electrically conducting material; means pivotally mounting said vane for rotation about said axis to traverse said slots and to cooperate with said lrst named blocks to comprise a capacitance network; means connected to said contact elements for impressing thereon alternating potentials of equal magnitude and of opposite phase with respect to a point of comparison, and means connected to said vane for responding to the potential diierence between said vane and said point.

13. In a device of the class described., in combination: a plurality of resistors in the form of circular arcs, connected together to comprise a closed circular resistance network; a like plurality of slotted blocks of electrically conducting material; means mounting said blocks about an axis with their slots inwardly directed in coplanar relationship; means connecting said blocks, in sequence, to points of connection of .said resistors, also in sequence; a pair of contact elements; means pivotally mounting said contact elements for rotative sliding upon said circular network in diametrically opposed relation; a vane of electrically conducting material; means pivotally mounting said vane for rotation about said axis to traverse said slots and for cooperation With said first named blocks to comprise a capacitance network; magnetic means,

Vcarried by said last named means, for causing stationary elements arranged in a circular conguration, tv/o mutually insulated movable ele- Y ments, and means mounting said movable elements for unitary rotation about an axis extending through said circular configuration, the elements of at least one of said impedance means being in the form of condenser plates and the movable elements thereof being spaced from the stationary elements by a substantially frictionfree dielectric; a source of alternating voltage of a selected frequency; means energizing the movable elements of said sending means from said source; means for independently rotating the movable elements of said sending and said receiving impedance means; means interconnecting stationary elements of said sending and receiving means, so that for each rotated position of said sending means there is a balance position of the movable elements of said receiving means in which they are both at the same potential, While in other positions there appears between them an alternating output voltage of the frequency of said source which varies in magnitude and reverses in phase With variat1on in the extent and reversal in the direction of their displacement with respect to the balance position; means energizing said motor, from Asaid source and from the movable elements of said receiving means, for operation which reverses With reversal in the phase of said output voltage and which ceases when said output voltage is zero; means mechanically connecting said motor to drive Said movable elements of said receiving impedance means in a direction to reduce said output voltage lto Zero and thus to rebalance the apparatus; and controlled means actuated by said motor.

15. In telemetric apparatus, in combination: a motor to be controlled; first and second'impedance means for controlling said motor, each said means comprising a plurality of stationary elements arranged in a circular conguration, a member movable with respect to said stationary elements, and means for causing rotation of said movable member about an'axis extending through said circular conguration, said movable member of one of said impedance means comprising a pair of operative elements and said movable member of the other of said impedance means comprising a single opera- 16 tive element; a source of `alternating voltage of selected frequency having a center tap; means energizing one of said impedance means from said source through the elements of said movable member; means for independently rotating said movable members; means interconnecting corresponding stationary elements of saidl rst and second impedance means so that for each rotated position of said single operative element there is a balance position of said pair of operative elements such that said single element is at the same potential as said center tap, while in other rotated positions of said pair of elements said single element assumes an alternating output voltage with respect to said center tap which varies in magnitude and reverses in phase with variation in the extent and reversal in the direction of the displacement of said pair of elements from said `balanced position; means energizing said motor, from said source and from said output voltage, for operation which reverses Ywith reversal in the phase of said output voltage and which ceases when said output voltage is zero; means mechanically connecting said motor to drive said movable member of said receiving impedance means in a direction to cause decrease in said output voltage and thus to rebalance the apparatus; and controlled means actuated by said motor.

16. In telemetric, apparatus, in combination: a motor to be controlled; sending and receiving impedance means for controlling said motor, each v'said impedance means comprising a plurality of stationary elements arranged in a circular configuration, a movable member including at least one movable element, and means mounting said member for rotation about an axis extending through said circular conguration, the stationary elements of said sending means being in the form of condenser plates cooperating with means including said movable element to comprise a plurality of variable condensers, said last named movable element being spaced from said stationvary condenser plates by a substantially frictionfree dielectric; a source of alternating voltage of a selected frequency; means-variably energizing the stationary elements of said receiving means, as compared to a point of fixed potential, from said source; means for rotating the movable members of said sending and said receiving means; means interconnecting corresponding stationary elements of said sending and receiving means so that for each rotated position of the movable member of said sending means there is a balance position of the movable member of said receiving means in which said apparatus gives no output voltage, While in other rotated positions of said movable member of said receiving means the apparatus gives an alternating output voltage of the frequency of said source which varies in magnitude and reverses in phase with variation in the extent and reversal in the direction of displacement of said rotatable member from said balance position; means energizing said motor, from said source and from said output voltage, i or operation which reverses with reversal in the phase of said output voltage and which ceases when said output voltage is zero; means mechanically connecting said motor to drive said movable member of said receiving means in a direction to cause decrease in said output voltage :and thus .to rebalance -the apparatus; and controlled means actuated by said motor.

WALDO H. KLIEVER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Number 18 Name Date Brown Aug. 25, 1931 Wittkuhns et al Aug. 14, 1934 Parker Nov. 3, 1936 Urfer Aug. 17, 1937 West Mar. 15, 1938 Eiokenmeyer Mar. 26, 1940 Moore 2 Aug. 6, 1940 West M9124, 1942 Greback July 28, 1942 Krussman et al Dec. 22, 1942 Parker Sent. 7. 1943 

